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ECAT Chemistry Chemical Equilibrium Test Online

Maan AliLast Updated: April 19, 2025

Chemistry Chemical Equilibrium MCQS Online Test

ECAT Chemistry Chemical Equilibrium Chapter Online Test

Total Questions:	63
Time Allowed:	30 Minutes
Total Marks:	63
How to Attempt Test:	Please choose the right Option in MCQ-type question.
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ECAT Chemistry Chemical Equilibrium Test

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Page 1 of 3

Chemistry

1. Chemical equilibrium is referred to as dynamic because, at equilibrium, the

Rates of the forward and backward reactions change

Equilibrium constant changes

Reactants and products keep reacting

Concentrations of the reactants and products continue to change

2. The rate of chemical reaction is directly proportional to the active mass of reactant this statement is known as ___________

Law of Equilibrium

Law of reaction

Law of Mass Action

None of these

3. Reaction which proceed in both the directions is called

Irreversible

Reversible

Non spontaneous

Spontaneous

4. Preparation of buffer solution can be done by mixing

Strong acid and its salt with weak base

Strong base and its salt with weak acid

Weak acid and its salt with weak base

Weak base and its salt with strong acid

5. If the value of kc is very low then the forward reaction will occur __________

Randomly

Slowly

Moderately

Fast

6. Which of the following is more acidic?

Bananas

Bread

Lemons

Apples

7. The equilibrium will shift towards right by increasing ___________ of reactants

Impurity

Pressure

Concentration

Temperature

8. Which of the following factors will favour the reverse reaction in a chemical equilibrium?

None of these

Increase in concentration of one of the products

Increase in concentration of one of the reactants

Removal of one of the products regularly

9. When pressure is applied to the given equilibrium ice water which of the following will happen

Water will formed

More water will be formed

Equilibrium will not be disturbed

More ice will be formed

10. The relationship between Kp and Kc is give by

Kc = Kp (RT)∆n

Kp = Kc (RT)∆n

Kp = Kc (RT)∆

Kp = Kc (RT)-∆n

11. Which set of solutes will form a buffer when dissolved in water to make 1 litter of solution?

0.4 mole of CH3COOH with 0.4 mole of NaOH

0.2 mole of NaCl with 0.2 mole of HNO3

0.0002M HCl

0.4 mole of NH3 with 0.2 mole of HCl

12. The product of [0H¯][H⁺] at 25C° is

10¯¹⁴

10¯²⁰

10¹⁰

10¯¹⁰

13. When ever a week a base is dissolved in water, it gives its conjugate acid similarly a weal acid in water products its conjugate base. The conjugate acid base pair is stated by

Law of mass action

Lowery Bronsted concept

Le – Chatelier’s principle

Common on effect

14. pH of milk is

6.5

7.5

15. When sparingly soluble salt is in equilibrium with molar concentration of its oppositely charged ion when the product is called

Solubility product

Dissociation constant for an acid

Dissociation constant

Common ion effect

16. In reversible reactions, if the forward reaction occur very fast then reactant (s) is (are) __________

Solids

Unstable

At very high temperature

Stable

17. In an exothermic reaction, a 10° rise in temperature will

Not produce any change in Kc

Decrease the value of equilibrium constant

Produce some increase in Kc

Double the value of Kc

18. Temperature for preparation of SO₃ is

400 – 500 °C

400 °C

200 °C

600 °C

19. A basic Buffer solution can be prepared by mixing

Weak acid and its slat with strong base

Strong acid and its slat wit weak base

Weak base and its salt with strong acid

Strong base and its salt with weak acid

20. A chemical reaction A ⇌ B is said to be in equilibrium when

Complete conversion of A to B has taken place

Conversion of A to B is only 50% complete

Only 10% conversion of A to B has taken place

The rate of transformation of A to B is just equal to rate of transformation of B to A in the system.

21. For a reaction H₂ + I₂ ⇌ 2HI at 721 K, the value of equilibrium constant is 50. If 0.5 moles each of H₂ and I₂ is added to the system the value of equilibrium constant will be

0.02

0.2

22. For equilibrium 2NO₂(g) ⇌ N₂O₄(g) + 14.6 kcal increase of temperature would

Favour the formation of N₂O₄

Stop the reaction

Favour the decomposition of N₂O₄

Not alter the equilibrium

23. At start of reaction, concentration of reactants are on

Lower side

Higher side

Optimum side

Constant

24. An equilibrium constant of 10¯⁴ for a reaction means that the reaction is

One that is very favorable and will have mostly product at equilibrium

The equilibrium constant only relates to the speed of a reaction and not to the amount of product formed

One that is unfavourable and will not have very much product at equilibrium

One that will have 50% product and 50% reactant at equilibrium

25. A buffer solution can be prepared by mixing

A weak base and its salt with strong acid

A weak acid and weak base

A strong acid and weak base

A strong acid and its salt

Page 2 of 3

26. Synthesis of ammonia by Habor process is an example of ___________

Decomposition Reaction

Reversible Reaction

Irreversible Reaction

Constant Reaction

27. Who studied the effect of temperature on equilibrium?

Vant Hoff

Lewis

Arrhenius

Van der Waal

28. In a reversible chemical reaction having two reactants in equilibrium, if the concentration of the reactants are doubled then the equilibrium constant will

Becomes one fourth

Remains the same

Also be doubled

Be halved

29. Which of the following aqeous solution will be basic?

NaCl

Na₂CO₃

Fecl₃₋

Na₂SO₄

30. Which one of the following is a buffer solution?

Solution of CuSO4

Glue

Brine

Blood

31. In a chemical reaction N₂ + 3H₂ ⇌ 2NH₃ at equilibrium point

The reaction has stopped

Equal volumes of N₂ and H₂ are reacting

The same amount of ammonia is formed as is decomposed into N₂ and H₂

Equal masses of N₂ and H₂ are reacting

32. AgCl dissolved with cone (2 x 10¯²) Ksp will be

3.6 x 10¯⁶

7.2 x 10¯⁶

4 x 10¯⁴

3.6 x 10¯⁵

33. Units of Kc is

Moles¯² dm⁺⁶

Moles² dm⁺⁶

Kc may or may not have units

Moles⁺² dm¯⁶

34. Kc > Products / Reactants favours

Reaction completed

Backward reaction

Equilibrium

Forward reaction

35. Water and ice are in equilibrium at 0C° and pressure is applied at this stage, then

More water is formed

More ice is formed

Equilibrium is not disturbed

Water evaporates

36. Which statements are correct for a reaction at equilibrium?
(I) The forward and reverse reactions both continue
(II) The rates of the forward and reverse reactions are equal
(III) The concentrations of reactants and products are equal

II and III only

I and II only

I, II and III only

I and III only

37. Le-Chatelier’s principle is sometime known as

Law of active mass

Law of mobile equilibrium

Law of mass action

All of these

38. When pressure is applied to the equilibrium system Ice ⇌ Water? Which of the following phenomenon will happen?

More ice will be formed

More water will be formed

Equilibrium will not be formed

Water will evaporate

39. Addition of CH3COOH and CH3COONa gives in water

Acidic buffer solution

Both b and c

Standard solution

Buffer solution

40. What can affect the magnitude of equilibrium constant Kp of a reversible gaseous reaction

Catalyst

Temperature

Pressure

None of these

41. Two moles of HI was heated in a sealed tube at 440°C till the equilibrium was reached. HI was found to be 22% decomposed. The equilibrium constant for dissociation is

0.0199

0.282

1.99

0.0796

42. The state of equilibrium refers to

State or rest

Dynamic state

State of inertness

Stationary state

43. If rate of concentration of reaction is equal to rate of concentration of products in reversible reaction the __________

Reaction goes forward

Equilibrium will established

Reaction goes backward

Reaction stops after some time

44. PH of human blood is

7.00

7.80

7.35

7.50

45. For the reaction 2A(g) + B(g) ⇌ 3C(g) + D(g) two moles each of A and B were taken into a flask. The following must always be true when the system attained equilibrium

[B] = [C]

[A] = [B]

[A] > [C]

[A] < [B]

46. The rate at which a substance reacts is directly proportional to its active mass and the rate of reaction is directly proportional to the product of the active mass of reacting substances is known as

None of all

Law of mass action

Le – Chatelier’s principle

Law of conservation of energy

47. Solubility of any salt can be determined from

Ksp

48. The factor which changes equilibrium constant o the reaction A₂(g) + B₂(g) → 2 AB(g) is

Total pressure

Catalyst

Amounts of A₂ and B₂

Temperature

49. Idea of PH and POH was put forward by

Gibbs

Sorenson

Chadwiick

Einstein

50. If a buffer solution of higher PH than seven is to be made we use

Weak base and its salt with a strong acid

Strong acid and strong base

Weak acid and strong base

Weak acid and its salt with a strong base

Page 3 of 3

51. By the addition of base in water pH will be

No effect

More than 7

Less than 7

Equal to 7

52. At certain temperature, 50% of HI is dissociated into H₂ and I₂ the equilibrium constant is

1.0

3.0

0.25

0.5

53. In reversible reaction the changes in forward and backward reaction occur _________

Both a and b

None

Simultaneously

Individually

54. What is the relationship between kp and kc?

kc = kp (P)-∆n

Kc - kp (RT)∆n

kp = kc (RT)∆n

kp = kc (RT)-∆n

55. Conjugate base of a very weak acid is

Strong base

Salt

Do not ionize

Weak base

56. The reaction 2SO₂ + 2O₂ ⇌ 2SO will be favoured by

High temperature and high pressure

Low temperature and high pressure

Low temperature and low pressure

High temperature and low pressure

57. When H₂ and I₂ are mixed and equilibrium is attained, then

HI dissociation stops

The reaction stops completely

None of these

Amount of HI formed is equal to the amount of H₂ dissociated

58. In which of the following cases, the reaction goes farthest to completion?

K = 10³

K = 10⁰

K = 10

K = 10¯²

59. The equilibrium constant in a reversible chemical reaction at a given temperature

Does not depend on the initial concentrations of reactants

Is not characteristic of the reaction

Depends on the initial concentration of the reactants

Depends on the concentration of one of the products at equilibrium

60. In an exothermic reversible reaction increase in temp shifts the equilibrium to

Product side

Reactant side

Remains unchanged

Fluctuate

61. When rate of forward reaction is equal to rate of backward reaction, then the equilibrium established is called

Dynamic equilibrium

None of all

Static equilibrium

Chemical equilibrium

62. Which of the following gives a basic buffer?

NH₄OH + NH₄Cl

NaOH + NaCl

NaCl + CH₃ COOH

NaOH + CH₃ COONa

63. Which pH is considered as basic?

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Maan AliLast Updated: April 19, 2025

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ECAT Chemistry Chemical Equilibrium Test Online

Chemistry Chemical Equilibrium MCQS Online Test

ECAT Chemistry Chemical Equilibrium Chapter Online Test

ECAT Chemistry Chemical Equilibrium Test

Chemistry

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